CUED Publications database

Active boundary-layer control in diffusers

Kwong, AHM and Dowling, AP (1993) Active boundary-layer control in diffusers. In: UNSPECIFIED.

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Abstract

© 1993 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Flow separation in diffusers leads to loss in energy recovery and is often a source of unsteadiness due to stall movements. This paper investigates the use of wall jets as a remedy to these problems. New jet geometries are compared to the conventional annular blowing. Steady wall jets are found to be capable of raising the mean pressure recovery in both conical and rectangular air diffusers, but high injected mass flow rates are required before the flow in rectangular diffusers becomes steady. Active feedback control is applied to reduce this flow unsteadiness. To implement the control, the air supplied through the wall jets is modulated in response to the unsteady pressures within the diffuser. Results are presented for two feedback mechanisms. Both are found effective with the level of attenuation well predicted by theory. A combination of steady and unsteady blowing is found capable of giving both a good mean pressure recovery and reduced pressure oscillations.

Item Type: Conference or Workshop Item (UNSPECIFIED)
Subjects: UNSPECIFIED
Divisions: Div A > Fluid Mechanics
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:01
Last Modified: 12 Oct 2017 01:53
DOI: